Casting apparatus

ABSTRACT

CASTING APPARATUS HAVING A VACUUM CHAMBER IN WHICH MOULDS TO BE FILLED ARE SUPPORTED. A FLEXIBLE SUPPLY DUCT FEEDS THE MATERIAL TO BE CAST TO THE MOULDS THROUGH A NOZZLE AND IS POSITIONABLE FROM OUTSIDE THE CHAMBER TO SEQUENTIALLY BRING THE NOZZLE INTO REGISTER WITH THE MOULDS WHILE THE CHAMBER IS EVACUATED. THE NOZZLE CAN BE URGED   AGAINST EACH MOLD WHILE IN REGISTER WITH IT TO PREVENT THE ESCAPE OF CASTING MATERIAL WHEN THE CASTING MATERIAL IS PLACED UNDER PRESSURE.

A Oct. 19, 1971 A. Y. STIRRAT 3,613,167

CASTING APPARATUS Filed July 23, 1969 2 Sheets-Sheet 1 Fi|8 I LEX //VV[/VMP A ANDER YQUN STIRRAT Oct. 19, 1971 A. Y. STIRRAT 3,613,167

CASTING APPARATUS Filed July 23 1969 2 Sheets-Sheet 2 //VV[/V/'ZP ALEXANDER YOU C STIPPAT 3 Mvn 4 M 4 United States Patent 3,613,167 CASTING APPARATUS Alexander Young Stirrat, Fairlawn, Broadstone, Dorset, England Filed July 23, 1969, Ser. No. 844,049 Claims priority, application Great Britain, July 26, 1968, 35,879/ 68 Int. Cl. B29c /00 US. Cl. 18-26 R 7 Claims ABSTRACT OF THE DISCLOSURE Casting apparatus having a vacuum chamber in which moulds to be filled are supported. A flexible supply duct feeds the material to be cast to the moulds through a nozzle and is positionable from outside the chamber to sequentially bring the nozzle into register with the moulds while the chamber is evacuated. The nozzle can be urged against each mould while in register with it to prevent the escape of casting material when the casting material is placed under pressure.

This invention relates to casting apparatus which can be used for encapsulating, impregnating or handling resin or materials containing resin.

According to this invention there is provided a casting apparatus comprising a vacuum chamber in which a plurality of moulds to be filled can be supported, a supply duct for feeding the liquid to be cast and having a supply nozzle or nozzles located within the chamber, positioning means operable from outside the chamber for bringing the supply nozzle or nozzles into register with the moulds in sequence while the chamber remains evacuated, and urging means for urging the or each supply nozzle against a mould with which it is in register to prevent the escape of liquid being cast.

Generally the supply duct is flexible or jointed.

Preferably the or each nozzle can be opened when it is not urged against a mould. This feature has the advantage that the apparatus can be used for gravity casting.

The apparatus is preferably provided with means applying pressure to the liquid being cast. The pressure may have many values, e.g. atmospheric pressure or a pressure greater or less than atmospheric.

Because of the provision of the positioning means operable from outside the chamber, a series of castings or injections of fluid into the moulds can take place without opening the chamber or altering the level of pressure inside it.

It is envisaged that the urging means comprise a spring, weight or fluid pressure means for exerting a preset force on the or each nozzle when it is in register with a mould, its force being suflicient to provide a seal between the or that nozzle and that mould. Preferably, the apparatus comprises a table for supporting the moulds.

If desired, any or all of the movements of the or each nozzle and of the table can be power or pressure operated with arrangements to ensure that the required force between the or a nozzle and a mould is reached but not exceeded.

The material being cast will generally be in a vessel outside the chamber and connected to the nozzle or nozzles inside the chamber, the vessel, if desired, being a closed vessel to enable it to be at a pressure different from the ambient pressure outside the chamber but at a higher pressure than that inside the chamber whilst connected to the nozzle or nozzles.

By this arrangement a number of receptables or ice moulds inside the vacuum chamber can in turn be filled and subjected to a difl'erential fluid pressure whilst retaining the vacuum in the chamber throughout the several castings.

It is envisaged that the or each nozzle guided on to a mould may automatically (a) apply the required force, (b) open a valve allowing the casting material to flow from the vessel into the mould under a combination of gravity and differential pressure, (c) apply the pressure throughout the interior of the mould once filled with casting material for as long as is preset, and (d) then rise clear of the mould ready to be guided to the next mould.

The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a vertical section of an apparatus according to the invention;

FIG. 2 is a section on the line AA of FIG. 1; and

FIG. 3 is an enlarged view of a detail of FIG. 1.

In the apparatus shown in the drawings, the chamber 1 may be evacuated to a low vacuum. A series of moulds 17 of varying heights and dimensions are placed on a horizontal round table 2 on to which the moulds are held by gravity. The pouring head 4 is supported on a horizontal arm 5 attached to a vertical shaft 6 passing outside the chamber through seals 18 in such a way that the head can be swung by handle 9 from the centre to the outside radius of the table. By also rotating the table again from outside the chamber by means of wheel 3, the head 4 can be positioned on any point above the table surface.

By a vertical movement of the shaft 6 the head can then be brought down to grip each mould 17 in turn.

This is effected by a motor (not shown) but controlled from switch 10 on handle 9 which turns a belt 13 around nut 11 and which is internally threaded to fit on a screw thread 12 on shaft 6.

A pivoted lever 14 rests on the nut 11 under tension of spring 19.

A switch 15 controlled by lever 14 can stop the motor.

A support 16 is provided for the nut 11.

The arm 5 is formed of three parts, 5a, 5b and 5c. Pivot 20 is the pivot between part 5a and the shaft 6. Pivot 21 is the pivot between part 5c and part 5a.

Part 50 is held to part 5b a spring 25 and carries a pin 22 extending through a seal 38 in the nozzle 4 to a valve head 23. The inlet for liquid to the nozzle is shown at 24. An arm 35 is bolted to arm 5a and projects through a slot 26 into the central passage 27 of the shaft 6 which is hollow, the arm 35 passing through a seal in the wall of the chamber 1. The end of the arm 35 within the passage 27 is secured to an operating rod 28.

In operation, for pressure casting, having positioned the nozzle 4 over a mould 17, switch 10 is pressed to lower the nozzle. As the mould stops the nozzle 4 from descending further, arm 5a swings about pivot 20. As arm 5a rises, arm 50 rotates on pivot 21 because of contact of arm 5c with cam 5b. This causes the other end of arm 50 to rise more rapidly than nozzle 4, opening the valve 23.

The spring 19 pulls down arm 14 and hence nut 11 and thus applies pressure to hold nozzle 4 down on to the mould 17.

Movement of the shaft 6 continues until and switch 15 stops the motor drive.

For gravity casting, having positioned nozzle 4 over a mould 17, rod 28 is operated moving arm 35 upwardly and rotary arm 5a about pivot 20 in the clockwise direction. As will be appreciated arm 5c rotates about pivot 21 to open nozzle 4 and liquid flows under gravity from nozzle 4 into the open mould.

What is claimed is:

1. A casting apparatus comprising a vacuum chamber in which a plurality of moulds to be filled can be supported, a supply duct for feeding the liquid to be cast and having at least one supply nozzle located within the chamber, positioning means operable from outside the chamber for bringing said supply nozzle into register with the moulds in sequence while the chamber remains evacuated, and urging means for urging said supply nozzle against a mould with which it is in register to prevent the escape of the liquid being cast under pressure.

2. An apparatus as claimed in claim 1 wherein the supply duct is flexible.

3. An apparatus as claimed in claim 1 wherein the said nozzle can be opened when it is not urged against a mould.

4. An apparatus as claimed in claim 1 wherein means are provided for applying pressure to the liquid being cast.

5. An apparatus as claimed in claim 1 wherein the urging means comprise means for exerting a preset force 4 on said nozzle when it is in register with a mould, the force being suflicient to provide a seal between said nozzle and that mould.

6. An apparatus as claimed in claim 1 which comprises a table for supporting the moulds.

7. An apparatus as claimed in claim 6 wherein the positioning includes means for rotating the table, means for rotating said nozzle about an axis parallel to but spaced from the axis of rotation of the table, and means for moving said nozzle axially in relation to the table.

References Cited UNITED STATES PATENTS GRANVILLE Y. CUSTER, JR., Primary Examiner U.S. Cl. X.R.

l830 GH 

